【 Weak current College 】 impact PLC's two main interference current, voltage 】

PLC has now been widely used in industrial production automation control equipment. However, because some of the production environment of the current or voltage of dramatic changes, the results PLC program operation error, causing an error entry and causes an error output, making the device out of control. Therefore, if you raise the issue of anti-interference PLC is increasingly widespread concern.

PLC system interference sources come mainly from some of the power network, electrical equipment and lightning, radio, radar and high frequency induction heating equipment. At present, in China, PLC and more serious industrial site is coming from the power supply and signal line is introduced. PLC power usually isolated power supply, its institutions and the manufacturing process factors that isolation is not satisfactory. In fact, since the distribution parameters especially distributed capacitance, absolute isolation is not possible. And PLC control system connection of various types of signal transmission lines, in addition to the transfer of effective information, there is an external interference signals.

As a rule of thumb we summarize the following main measures: a antijamming

1. in the PLC control system, power supply has a very important position. Select the distribution capacity is small, the restraint straps (such as multiple and screened and leakage technology) with electrical appliances, in order to reduce the interference of the PLC system.

2. in order to reduce the power cable to the radiation of electromagnetic interference, in particular the frequency converter feed cable. Using copper tape armored shield power cable, reducing the power line production of electromagnetic interference.

3, due to the complexity of electromagnetic interference, to eradicating meet interference is not possible, therefore in the PLC control system software design and configuration, you should also carry out anti-jamming on the software side, further improve the reliability of the system.

4. perfect grounding system is the PLC control system resistance to electromagnetic interference of one of the important measures.

PLC control system interference is a very complex issue, so in comprehensive anti-jamming design should take into account various factors that a reasonable and effective suppression of anti-interference, on some interference also need to do a detailed analysis, take the remedy to the way that we can make the PLC control system to work properly.